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Home >> Mazda >> 2007 >> B4000 SE, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 70 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P1518, DTC P1519, DTC P1520, DTC P1537 Or DTC P1538 >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Mazda B4000, 2003 Mazda B3000, and 2003 Mazda B2300. However, it is still accessible from the selected car via links, so may be relevant.
  1. If QUICK TEST was not performed, go to QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If QUICK TEST was performed, go to next step.
  2. Check Swirl Control Valve Monitor (SCVM) Circuit Voltage -  Turn ignition off. Turn ignition off. Disconnect PCM 104-pin harness connector. Connect Breakout Box (49-UN01-130) to PCM harness connector and PCM. See Figure . With KOEO, measure SCVM circuit (White wire) voltage between breakout box terminal No. 8 and ground. See Fig 1 . If Swirl Control Valve Monitor (SCVM) voltage reading is less than one volt, go to step  7 . If SCVM voltage reading is one volt or more, go to next step.
    Fig 1: Identifying SCVM & Intake Manifold SCSV Harness Connectors Circuit Identification
    G00155559Courtesy of MAZDA MOTORS CORP.
  3. Perform Intake Manifold Swirl Control (IMSC) Functional Test -  With KOEO, using scan tool, access OUTPUT STATE CONTROL (OSC). Select DATALOGGER from TOOLBOX MENU. Deselect all PIDs from PID screen. Select IMRC# PID. Press FAULT box and MODE# box at bottom of screen. Select GRAPH tab (IMRC# and IMRC should be visible). Select IMRC# PID. Select OSC button on right side of screen (pointing finger). Command IMSC on (with IMRC# PID) and verify IMSC solenoid valve actuates, opening butterfly plate lever. If IMSC solenoid valve actuated, go to step  9 . If IMSC solenoid valve did not actuate, go to next step.
  4. Check Swirl Control Solenoid Valve VPWR Circuit For An Open In Harness -  Disconnect IMSC solenoid valve 2-pin harness connector. Measure VPWR circuit (Light Blue/Orange wire) voltage between IMSC solenoid valve harness connector and ground. See Fig 1 . If VPWR voltage reading is more than 10.5 volts, go to next step. If VPWR voltage reading is 10.5 volts or less, repair open circuit in Light Blue/Orange wire between battery junction box and IMSC solenoid valve harness connector. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step  22 .
  5. Check IMSC SIG Circuit For Open In Harness -  Turn ignition off. Disconnect PCM 104-pin harness connector. Connect Breakout Box (49-UN01-130) to PCM harness connector only. See Figure . Check continuity of IMSC SIG circuit (White/Orange wire) between breakout box terminal No. 42 and IMSC solenoid valve harness connector. If continuity is present, go to next step. If continuity is not present, go to step  22 .
  6. Check IMSC SIG Circuit For Short To VPWR In Harness -  Connect PCM to breakout box. With KOEO, measure voltage of IMSC SIG circuit (White/Orange wire) between IMSC solenoid valve harness connector and ground. See Fig 1 . If voltage reading is less than 10.5 volts, problem is intermittent. See INTERMITTENT  testing under SYSTEM TESTS. If voltage reading is 10.5 volts or more, repair short circuit in White/Orange wire between PCM 104-pin harness connector terminal No. 42 and IMSC solenoid valve harness connector. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step  22 .
  7. Verify Trouble Shooting Of DTCs Completed -  Turn ignition off. Disconnect IMSC solenoid valve harness connector. Disconnect SCVM 3-pin harness connector. Measure resistance of IMSC SIG circuit (White/Orange wire) between IMSC solenoid valve harness connector and ground. Record reading. Measure resistance between SCVM 3-pin harness connector IMSC SIG circuit (White/Orange wire) and SCVM 3-pin harness connector SIG RTN circuit (Gray/Red wire). Record reading. Measure resistance between IMSC solenoid valve harness connector IMSC SIG circuit (White/Orange wire) and SCVM 3-pin harness connector SCVM circuit (White wire). Record reading. If any resistance reading is more than 10,000 ohms, replace faulty intake manifold. After repair, go to step  22 . If all resistance readings are 10,000 ohms or less, go to next step.
  8. Check IMSC Driver Circuit For Short To Ground Or Monitor Circuit With PCM Disconnected -  Disconnect PCM 104-pin harness connector. Measure resistance between IMSC solenoid valve harness connector IMSC SIG circuit (White/Orange wire) and ground. See Fig 1 . Record reading. Measure resistance between IMSC solenoid valve harness connector IMSC SIG circuit (White/Orange wire) and SCVM 3-pin harness connector SIG RTN circuit (Gray/Red wire). Record reading. Measure resistance between IMSC solenoid valve harness connector IMSC SIG circuit (White/Orange wire) and SCVM 3-pin harness connector SVCM circuit (White wire). Record reading. If any resistance reading is more than 10,000 ohms, replace faulty PCM. After repair, go to step  22 . If all resistance readings are 10,000 ohms or less, repair appropriate circuit for a short. After repair, go to step  22 .
  9. Check SCVM Circuit To Determine Path For Possible Short -  Disconnect SCVM 3-pin harness connector. Measure voltage between SCVM 3-pin harness connector SCVM circuit (White wire) and ground. Record reading. Measure voltage between SCVM 3-pin harness connector VREF circuit (Brown/White wire) and ground. If SCVM voltage reading is equal to VREF voltage, go to next step. If SCVM voltage reading is not equal to VREF voltage, go to step  14 .
  10. Check SCVM Circuit To Determine A Short To VPWR -  Turn ignition off. Disconnect PCM 104-pin harness connector. Connect Breakout Box (49-UN01-130), to PCM harness connector and PCM. See Figure . With KOEO, using scan tool, access Output State Control (OSC). Select DATALOGGER from TOOLBOX MENU. Deselect all PIDs from the PID screen. Select IMRC# PID. Press FAULT box and MODE# box at bottom of screen. Select the GRAPH tab (IMRC# and IMRC should be visible). Select IMRC# PID. Select the OSC button on right side of screen (pointing finger). Command IMSC on (with IMRC# PID). Measure SCVM circuit voltage between breakout box terminal No. 8 and ground. If SCVM voltage reading is less than one volt, go to next step. If SCVM voltage reading is one volt or more, go to step  16 .
  11. Check SCVM Circuit For Short To VPWR At SCVM Harness -  Disconnect SCVM 3-pin harness connector. With KOEO, measure voltage between SCVM 3-pin harness connector SCVM circuit (White wire) and ground. See Fig 1 . If voltage reading is more than 10.5 volts, go to next step. If voltage reading is 10.5 volts or less, go to step  13 .
  12. Determine Short To Power With PCM Disconnected -  Turn ignition off. Disconnect PCM 104-pin harness connector. With KOEO, measure voltage between SCVM 3-pin harness connector SCVM circuit (White wire) and ground. If voltage reading is less than 10.5 volts, repair short circuit in White wire between SCVM 3-pin harness connector and PCM 104-pin harness connector terminal No. 8. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step  22 . If voltage reading is 10.5 volts or more, replace faulty PCM. After repair, go to step  22 .
  13. Check Monitor For Short To VPWR At SCVM Solenoid Valve -  Turn ignition off. Disconnect SCVM solenoid valve 3-pin harness connector. Measure resistance between SCVM 3-pin harness connector SCVM circuit (White wire) and VREF circuit (Brown/White wire). See Fig 1 . If resistance reading is more than 10,000 ohms, possible intermittent concern. See INTERMITTENT  testing under SYSTEM TESTS. If problem is not intermittent, replace faulty PCM. After repair, go to step  22 . If resistance reading is 10,000 ohms or less, replace faulty SCVM solenoid valve. After repair, go to step  22 .
  14. Determine IMSC Monitor Circuit Short To Ground -  Turn ignition off. Connect SCVM 3-pin harness connector. Disconnect PCM 104-pin harness connector. Connect Breakout Box (49-UN01-130) to PCM harness connector and PCM. See Figure . With KOEO, measure SCVM circuit (White wire) voltage between breakout box terminal No. 8 and ground. Record reading. Disconnect SCVM 3-pin harness connector. Measure SCVM circuit voltage between breakout box terminal No. 8 and ground. Record reading. If voltage reading changed from less than one volt to VREF when disconnecting SCVM 3-pin harness connector, replace faulty SCVM solenoid valve. After repair, go to step  22 . If voltage reading did not change from less than one volt to VREF when disconnecting SCVM 3-pin harness connector, go to next step.
  15. Check IMSC Monitor Harness For Short To Ground -  Turn ignition off. Disconnect PCM from breakout box. Measure resistance between SCVM 3-pin harness connector SCVM circuit (White wire) and SIG RTN circuit (Gray/Red wire). See Fig 1 . If resistance reading is more than 10,000 ohms, replace faulty PCM. After repair, go to step  22 . If resistance reading is 10,000 ohms or less, repair short circuit. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step  22 .
  16. Check Monitor Circuit Response -  Turn ignition off. Disconnect SCVM 3-pin harness connector. Disconnect PCM 104-pin harness connector. Connect Breakout Box (49-UN01-130) to PCM harness connector and PCM. See Figure . With KOEO, measure voltage of SCVM circuit between breakout box terminal No. 8 and ground. Record reading. Connect a fused jumper wire between SCVM 3-pin harness connector SCVM circuit (White wire) and ground. See Fig 1 . Record reading. If voltage reading cycled from VREF to less than one volt when inserting fused jumper wire, go to next step. If voltage reading did not cycle from VREF to less than one volt when inserting fused jumper wire, go to step  20 .
  17. Check SIG RTN Circuit Continuity With PCM Connected -  Turn ignition off. Check continuity between SCVM 3-pin harness connector SCVM circuit (White wire) and breakout box terminal No. 91. See Fig 1 . If continuity is present, go to next step. If continuity is not present, go to step  19 .
  18. Check Monitor Line For Intermittent Open -  Check continuity between SCVM 3-pin harness connector SCVM circuit (White wire) and breakout box terminal No. 8 while wiggling and bending harness from SCVM harness connector to PCM connector. If continuity is present all the time, replace faulty SCVM. After repair, go to step  22 . If continuity is not present all the time, repair intermittent open circuit in White wire between SCVM 3-pin harness connector and PCM 104-pin harness connector terminal No. 8. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step  22 .
  19. Check SIG RTN Circuit Continuity With PCM Disconnected -  Disconnect PCM 104-pin harness connector. Check continuity between SCVM 3-pin harness connector SCVM circuit (White wire) and breakout box terminal No. 91. See Fig 1 . If continuity is present, problem is possibly intermittent. See INTERMITTENT  testing under SYSTEM TESTS. If problem is not intermittent, replace faulty PCM. After repair, go to step  22 .
  20. Check Monitor Circuit Continuity -  Turn ignition off. Disconnect PCM 104-pin harness connector. Check continuity between SCVM 3-pin harness connector SCVM circuit (White wire) and breakout box terminal No. 8. See Fig 1 . If continuity is present, go to next step. If continuity is not present, repair open circuit in White wire between SCVM 3-pin harness connector and PCM 104-pin harness connector terminal No. 8. After repair, go to step  22 .
  21. Check Monitor Line For Intermittent Open -  Check continuity between SCVM 3-pin harness connector SCVM circuit (White wire) and breakout box terminal No. 8 while wiggling and bending harness from SCVM 3-pin harness connector to PCM 104-pin harness connector. See Fig 1 . If continuity is present all the time, replace faulty PCM. After repair, go to next step. If continuity is not present all the time, repair intermittent open circuit in White wire between SCVM 3-pin harness connector and PCM 104-pin harness connector terminal No. 8. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to next step.
  22. IMSC Repair Verification Drive Cycle -  Reconnect all electrical connectors. Using scan tool, clear DTC from PCM memory. While observing traffic laws, perform 3 accelerations from stop to more than 3500 RPM engine speed. Using scan tool, retrieve DTCs. See QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If same DTC is present, replace faulty PCM and repeat QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If any other DTC is present, go to applicable procedure for other DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS  . If no DTC is present, trouble shooting is complete.
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